维管射线是由射线原始细胞分裂，分化而成，因此是次生结构，所以也称次生射线(secondary ray)， 维管射线具有木射线通过形成层的射线原始细胞和韧皮射线相连，共同构成维管射线，有横向运输和贮藏养分的作用。
维管射线发达，周皮发育明显。
The vascular ray was developed and the development of periderm was obvious.
维管形成层属于侧生分生组织，包括能够产生次生木质部与次生韧皮部的纺锤状形成层原始细胞和产生髓射线的射线原始细胞。
It is a lateral meristem and contains fusiform initials giving rise to secondary xylem and phloem and ray initials giving rise to medullary rays. See also secondary growth.
从横切面上观察到，不定根原基起源于髓射线与维管形成层交叉的部位。
From cross sections of stems-cuttings, a primordium of adventitious roots originates from the cross region of pith rays and vascular cambium.
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